Railway traffic controlling apparatus



B. E. OHAGAN Filed April 16, 1932 RAILWAY TRAFFIC CONTROLLING APPARATUS A ril 25, 1933.

49 E ax Patented Apr. 25, 1933 UNITED s'rA ammo a. OHAGAN, or SWISSVALE, PENNSYLVANIA, ASSIGNQR r 'rna-vNroN swrrcn & SIGNAL COMPANY,OF swIssvALE, PENNSYLVANIA, a-coaroaa'rroN OF PENNSYLVANIA Application filed April is,

I signaling influences both ways between carcarried apparatus and trackwaydevices by beams of light. In this instance, one such influence is utilized for clearing a trackway tripping device at a stop signal so that the car or other railway vehicle may proceed past the stop signal without making it necessary forit to cometo a complete stop, and the car apparatus is so arranged that when the trackway device has been so cleareda low speed limit is imposed on the car until a clear signal is passed. Once a low speed limit is established for a car, a complete exchange of influences from the car to the trackway and then from the trackway back to the car, by beams of light, is utilized to effect the release of the low speed condition. Itwill be understood, however, that I do not limit myself to this particular use of such exchange of influencesby light beams, and the form of apparatus here shown will serve to illustrate only one of the different ways inwhich such exchange ofinfluencos between car-carried and trackway equipment can be made to perform a useful function. Other features of my invention will appear as the specification rogresses; i

, In order t at my inventionwill be more fully understood, I will describe one form ofapparatus embodying my invention, and will then point out the novel features thereof in claims. I w In the accompanying drawing, Fig. 1 is a diagrammatic view of one form of car-carried' apparatus embodying my invention. Fig. 2 is a diagrammaticview of one form of trackway apparatus also embodying my invention, and adapted to cooperate with the car-carried apparatus of Fig. 1. v

In Fig. 1, the reference character 19 designates atrip armthat is suspended from the body or truck of a car in the customary RAILWAY TRAFFIC CONTROLLING APPARATUS" 1922. Serial No.1 605,653.

manner to clear and-road ed qu inment but yet in a position to engage a trackway trip arm to be referred to later a or other, 7

It will be understood that the car railway vehicle is provided with the usual standard air brake equipment of which a pipe designated by the reference "character BP isthe brake pipe which, when vented to atmosphere, will cause an automaticapplication of the brakes. 7 Connected with the brake pipe BP is a brake application" valve BV, comprising a valve member 21 which TENS PATE T omen?- is biased by a spring 22 to such position as to close an exhaust port 23 leading to atmos} phere. The pressure onthe two sides of the valve member 21 is equalizedby a small connecting port 21 in the-member, whereby when the pipe 13 connected to therighthand side of the valve is closed,the pressure is equalized and the valve member'21occupies its left-hand position closing the exhaust port 23. When pipe 13 is opened to atmosphere, however, the pressure on the right-hand side of member 21 is reduced, whereupon the brake pipe pressure on the left-hand side of the memberwill cause the member to be moved. to the right to vent the brake pipe BP to atmosphere through the port 23.

Connected directly to the pipe 113 is a magnet valve MV and through a second pipe 2 a pilot valve PV. The pilot;valve PV' is actuated bg the trip arm 19 which projects downwari to engage each trackwav trip arm, as willappear later, when suc 1 trackway trip arm is in its trippingposition, but not when the trackway 'trip arm is in its nontripping position. The carcarried trip arm 19 is biased to amid position so that automatically returns to that position after it has been swung to either the right orleft. Whenever. the trip arm 19 is swung out ofits vertical position, a cam 3 attached to the arm 19 will raise a roller 4 attached to a. vertical sliding member 5, and this member 5, in turn, willr'aise a valve 6""which is attachedto a sliding. iston 7. The pipe 2 enters the lower end 0' the. casing of the pilot valve PV and is .shut off from atmosphere -when the valve 6 is the valve will close.

closed. When the valve 6 is raised by an operation of the trip arm 19, a passage 9 will be connected to atmosphere, through an exhaust port 10, reducing the pressure above the piston 7. The pressure in the pipe 2 acting on the underside of the piston will cause the piston to rise further against the action of a s ring 11, thus providing a direct commun cation from pipe 2 through valve 6 and port 10 to atmosphere. As the pressure in pipe 2 is reduced, spring 11 will tend to close valve 6, but the valve is so constructed that the direct exhaust from pipe 2 is cut off before piston 7 reaches its lowest position. It follows that the outflowing air will maintain a differential pressure on piston 7 to hold valve 6 open. When the pressure in pipe 2 is reduced low enough so that the pressure exerted below the piston 7 is less than the pressure exerted by spring 11,

The small communieating port 9 permits pressure to be norlimit of ten miles per hour,

mall equalized on both sides of the piston 7. valve device of this character is disclosed in United States Patent N o. 1,243,7 82, "ranted to \V. V. Turner on Oct. 23, 1917, for automatic train control; The pipe 13 is also shut off from atmosphere by the valve 12 of the magnet valve MV as long as its magnet 14 is energized. It follows that as long as magnet 14 is energized and the trip arm 19 is in its vertical position, the brake valve BV will hold the exhaust port 23 closed. Whenever the magnet 14 of magnet valve MV is deenergized, the pipe 13 will be connected to atmosphere through the valve 12 and the port 20; and whenever the trip arm 19 is moved out of its vertical position, the pipe 13 will be connected through pipe 2, valve 6, and port 10 to atmosphere; and in either case the brake valve BV will be actuated to open the exhaust port 23.

Each car or railway vehicle is equipped with a speed governor designated in Fig. 1 by the reference character G. This speed overnor, as here shown, is of the inertia y ball t pe, and the shaft 15 on which the fly ba ls are mounted is driven by a car axle through the medium of gears 16. This speed governor G operates a single circuit controlling contact 17 which is so adjusted that its contact is closed, as shown in Fig. 1, at all speeds below some predetermined low speed which I will speak of in this description as being ten miles per hour. At all speeds above this predetermined low speed the contact 17 is open. It is obvious that any other predetermined speed limit may be selected should it seem desirable to do so.

The magnet 14 of the magnet valve MV may be energized by either one of two circuits. One of these circuits is from the positive terminal B of a convenient source of current not shown, through back contact 24 of a slow release relay 25 to be described later, wire 26, front contact 27 of an acknowledging relay 28 also to be referred to later wire 29, and winding of magnet 14, to the negative terminal C of the current source. The second circuit extends from the terminal B through contact 17 of speed governor G when the speed is at or below ten miles perhour, wire 29, windin of magnet 14, and thence to the terminal It follows that magnet 14 is energized whenever the speed of the car is at or belowten miles per hour irrespective of the condition of the two relays 28 and 25, and is also energized when relay 25 is deenergized and relay 28 energized irrespective of the speed of theear.

The acknowledging relay 28 is normally energized by virtue of a stick circuit from the terminal B of thecurrent source, through its own front contact 30, contact 32 of a manually operated acknowledging key 31, and winding of relay 28, to the terminal C of the current source. The pick-up circuit for relay 28 extends from the terminal B through the front contact 33 ofthe relay 25, wire 34, contact 32 of key 31, and thence thrl'ogh the winding of relay 28 to the termina Carried on the car is tocell 35 and a relay 36 associated therewith. This light sensitive cell may be any one of several types well known to the art, and it is considered sufficient for thisv application to point out that normally the cell prevents suflicient current flowing from a battery 37 through the winding of the relay 36 to causethis relay to close its front contact 38. The cell 35, upon being exposed to a beam of light of high intensity,

"is so influenced as to permit current of sufficient value to flow from cause relay 36 to close its When contact 38 closes, it completes va simple circuit for the slow release relay. Thus normally both relays 25 and 36 are deenergized, but the exposing of the photocell 35 to a beam of light of high intensity results in both relays being picked up; When the acknowledging key 31 is manuallydepressed, the stick circuit for relay '28 will be ruptured and that relaywill become deenergized. If the key 31 is held depressed after rel'ay 28 becomes deenergized, a circuit .will be closed to a lamp 40 of a car-carried projector, designated by the reference character 41, thereby causing a beam of light of high intensity to be projected from the car towards the trackway, for a purpose which will be explained hereinafter. This circuit for the lamp 40 includes back contact 42 of key 31, back contact 43 of relay 28, and lamp 40. It follows that when the operator depresses the acknowledging key 31, the

the battery 37 v to a light sensitivephofront contact 38.

'mally lighted, by virtue of a circuit that includes the front contact 30 of relay 28, to

normally indicate to the operator the condition of that relay. It is to be noted that indicator lamp 44 will also be lighted when the relay .25 is picked up even though the relay 28 is at the time deenergized. The reason for lighting the indicator lamp 44 at the time rela 25 is energized will be pointed out when t e operation of apparatus is described.

Referring now to Fig. 2, the reference characters 1 and lfdesignate the trafiic rails of a stretch of track over ,which-traflic normally moves in the direction indicated by the arrow. insulated rail joints 46 to form a plurality of successive track sections, of which only.

one section XY is shown in the drawing. The track section XY of Fig. 2 is provided with a standard track circuit consisting of a convenient source of current such as the secondary 45 offa track transformer T connected across the rails 1 and 1 at the outgoing end ofthe section, and a track a relay TR connected across the rails at the entrance end of thesection. Traffic through the section XY is governed by a wayside signal S which may be of any standard type such as a color light signal. The operating circuits for the signal S are governed in part at least, by a home relay'H in accordancewith standard practice. As these operating circuts for signal S form no part of my invention, they are omitted from the figure to simplify the disclosure. As is the usual practice'when automatic stops are installed in connection with wayside signals, the home relay H is controlledby the track relays of two track sections in advance of the signal. To be explicit, the home relay H is energized by a circuit extending from the terminalBX of a source of current (not shown) through front contact 47 of the track relay TRl for the section in advance of section XY, line wire 48, front contact 49 of track relay TR for section X-Y,

- winding of relay H, and thence to the CX terminal of the same source of current. It follows that relay H is deenergized when either the section X-Y or the section next in advance is occupied, and is energized when and only when both of these sections are unoccupied.

At each signal location there is provided an" automatic stop mechanism indicated by the reference character ST which is ada ted to operate a trackway trip arm 50. he trip arm 50 is positioned to engage the carcarried trip arm 19. The automatic stop mechanism ST ma take any one of several forms, but a pre erred form is that dis- These rails are divided by the usual I the BX terminal through 56 of track relay TR, wire 57, circuit controlling contact 53 wire 55, and winding of (5 Thus when closed and claimed in the United States Patent 1,775,811, grantedSept. 16, 1930, to J. P. Coleman, for railway traflic controlling apparatus, and to which reference is made for a full description of-such automatic stop mechanism. For this application, it is thought sufficient to say that when the magnet 51 is energized, the trip arm 50 is moved to a horizontal or nonstripping position, but when magnet 51 is deenergized, the trip arm 50 movesto a vertical or tripping position. A circuit controlling contact 53 is also actuated by the mechanism ST in such a manner that it occu ies the position shown in the drawing w en the trip arm 50 is lowered to its non-tripping position, and is moved to the position indicated by dotted lines when the trip arm 50 is raised to its trippin position. Al-

though, as illustrated in t e drawing, the.

trip arm 50 is located some little distance in advance of the signal S, this is done only to avoid crowding the drawing. In practicing my invention, the trip arm is usually located but a few feet in advance of the insulated rail 'oints at the entrance of the associated trac section.

The magnet 51 of the automatic stop mechanism ST is normally energized by virtue of a circuit extending from the BX terminal of the current source, through front contact 54 of the home relay H, were 55, and winding of magnet 51, to the CX terminal of the current source. Once the tri arm ,50 is lowered, and the circuitcontro ling contact 53 closed, the magnet 51 may be retained energized a circuit from t e back contact magnet 51, to the X terminal. a car enters the section X--Y under a clear signal with the trip arm 50 lowered, the

magnet .51 will be retained ener 'zed and the tri arm 50 held in its lowere position until t e car has passed over the trip arm and has vacated the section X'Y, so that when multi le unit trains are operated over the railroa the forward cars' will not trip the rear cars of the same train.

Another auxiliary circuit is provided for the magnet 51 that passes from the BX terminal of the current source, through back contact 56 of the track relay, TR, wires 57 and 58, front contact 59 of a.slo w release relay 60 to be shortly described, wires Y61 and 55, and winding of magnet 51, to the terminal OX. Thus by means of this auxiliary circuit, the magnet 51 can be energized in the event the track relay TB. is shunted and the relay 60 ioked up-,=.. irrespective of the conditlon o the home relay H. That is, in the event the relay 60 is picked up, a car enteringthe section and shunting the track relay TR willcau'se III f the relay 63. The relay 63, when. p

way.

practice of ,my invention, the trackway.

the trackway trip arm 50 to be moved to its non-tripping position eventhough the home lVhen the cell 62 is exposedto a beam of.

light of high intensity it will cause s'ufii cient currentto pass from a battery 64 to energize the relay 63, but normally not sufiito pick up icked up, closes at its front contact 65 a simple circient current flows in the circuit fcuit to energize the relay 60, which circuit will bereadily understood by an inspection of the drawing. At each trackway trip arm location, there is also rovided arlamp 66 and a track projector 6?. The lam 66 may be energized by virtue of a circuit rom the BX terminal, through front contact 68 of the home relay H, front contact 69 of relay 60 when that relay is energized, and lamp 66, to the CX terminal of the current source. It follows that exposing the trackway cell 62 to a beam of light of high intensity will result in relay 63 being energized, and then relay 60, in turn, being pickedup, so that, in the event relay His picked up, the trackway lamp 66 will be illuminated and a beam of light of hi h intensit will be projected from the trac t is to be understoodthat in the photocell 62 is so located with respect to the trip arm 50 and the entranceof the track section XY that it will come within @the path of the beam of light projected by the car-carried projector 41 just after the car has entered the track section and shunted. the trackrelay TR but before the carcarried trip arm 19 engages the trackway trip arm 50. It will be further understood that the car-carried photocell and the trackway projector 67 are so positioned that the car-carried cell comes within the path of the beam of light projected from the track projector 67 at the same time or just after the beam of light from the car-carried projector has fallen upon the trackway cell 62 In describing the operation of my system, I will assume both the car-carried apparatus and the trackway apparatus to be in the conditions illustrated in Figs. 1 and 2, respectively. It is apparent that when the car passes the signal S in its clear position and enters the section XY, it will shunt the track relay TR. This will deenergize the relay H and so will set the signal S at stop in the customary manner, and it will also complete at the back contact 56 the stick circuit for retaining the magnet 51 energized to hold the trip arm 50 lowered in its non-tripping, position. The car-carr'ied trip arm will thus not engage the trackway arm 50 and the car can travel through the section X-Y at full speed. As the car passes out of the section XY and enters the section next in advance, the shunting of the track relay TRl will keep the relay H deenergized. The picking up of the track relay TR as the car vacates the section X-Y will open the back contact 56 in the stick circuit to the magnet 51, and as relay H is ,now deenergized, the trip arm 50 is raised to its tripping position.

Assuming a second car approachesthe stop signal while the first car occupies the section to the right of section X-Y, the trip arm 50 will be in the tripping position, and in the event the operator attempts to pass signal S, the car-carried trip arm 19 will engage the trackway arm 50 with the result that an automatic brake application is initiated in the manner described hereinbefore. To pass the stop signal S without an automatic application of the brakes, the operator on the second car will depress the acknowledging key 31, thus rupturing the stick circuit for the acknowledging relay 28, so that this relay will be deenergized. The opening of the acknowledgin relay 28 will remove the normal supply 0 current from the magnet 14: of magnet valve MV, so that the magnet can now be energized only through the contact 17, of the speed'governor The operator will hold the key 31. depressed atter the relay 28 is deenergized, so that the lamp will be illuminated causing a. beam of light of high intensity to be pro- 'made slow-releasing so as to retain the circuitof magnet 51 closed until the trip arm is lowered and the circuit controlling contact 53 closed. This second car can now pro ceed through the section XY, but cannot exceed the speed at which contact 17 opens, which speed I have assumed to be ten miles per hour. If the trip arm at the next signal is in its tripping position, the. operator of the car must again depress the acknowledging key 31 to again light the lamp 40. This action must be repeated each time the car approaches a trip arm in the tripping position. At no point after the car passed the first such trip arm can the car exceed the low speed limit Without an automatic brake application until a clear signal is reached.

If a cartravelingunder speed restriction approaches a clear signal, the operator will depress the acknowledging key 31 as before to energize the lamp40. "The light beam from the car, striking the photocell 62, will cause'thc trackway relay 60 to be picked up and, as relay H is now ener ized, the trackway lamp 66 will become lig ted. The light.

beam from the trackway projector 67 will strike the photocell 35 on the car and so will cause both relays 36 and 25 to become energized. The energizing of relay 25 will close the pick-up circuit for "the acknowledging relay 28, and as soon as the operator releases the acknowledging key 31, the relay 28 will become energized, reclosing the noran elevated trackway triparm in the event the relay 36 associated with the light sensitive cell 35 should fail to open. That is to say, a check is provided to insure the return of photocell 35 and its relay 36 to their.

' a safe or unsafe, a car-carried brakeapplying normal inactive conditions.

In the case of the wayside apparatus, if

relay 60 should be retained energized due to failure of relay 63 to open, the'only effect would be that the trip arm 50 might" clear when a car enters the section X-Y':

even though the operator on the car does not press his acknowledging key. This condition, however, would not be likely to arise, because the car operatorwould not have any way of knowing that he could pass'thetrip arm without operating his acknowledging key.

Although I have herein shown and described only one form to a non-tripping or a tripping position according as trafiic conditions in advance are safe or unsafe, a car-earned brake applying trip arm arranged to be operated by the trackway trip arm when'the latter isin its tripping position but" not when it is in its non-tripping position,

of light, manually controlled means adapt:-

of apparatus em--- bodying my invention, it is understood that may be a car-carried source ed when actuated to illuminate said source of light, a light sensitive trackway element influenced by said light source toelfect the] 7' movement of the trackway trip' 'armi t it non-tripping position under unsafe traflic conditions, and car-carried speed governing means rendered active to establish a low I speedwrestriction' in response to such actua- 2 tion' ofthe manually controlled means.

2aRailway trafiic controlling apparatus comprising, a. trackway atrl arm movable to 21 non-tripping or a tri'pplng position ac- I cording-as traihc condit onsin advance are] safe or unsafe, a C -C brake trip arm arranged to be operated .by the,

track'way trip arm when the latter is in its .tripplng positlon but not when it is in its, :non-trippingposition, a car-carried source of light, manually controlled means'adapted when actuatedto render said source of a light active, alight sensitive trackway.ele-.

ment influenced by light from said source to effect the movement of the trackivay trip 1 arm to its non-tripping position underarm safe'traflic conditions, and car-carried speed governing means rendered active to estabh 11311 a low speed IGStIlCtlOIl n response'to said actuationof the manually controlled means 1 j,

3. Railwaytrafiic controlling apparatus comprising, a trackway trip arm movable to a non-tripping or a tripping position according astrafiic conditions in advanceare ytrip arm arranged to be operated by the,

trackway trip arm when the latter is in its tripping position only,i a normally inactive.

trolled 1 means torender active said sourcefluenced by thelight from said source, and 1 means governed by saidtrackway device efcar-carried sourceof light, manually con-,

of light, a trackway photoelectric device infectiveito movethe trackway trip arm to.

its non-tripping position under unsafeltraffic conditions 111 response to the influence on the :trackway device of the light from said source.

4. Railway ma ednjtiouing appar tus comprising, a car-carried means arranged to at times establish a low speed restriction for the car, a car-carried source oi light and a car-carried light sensitive cell, atrackway source of light and a trackway light sens tive cell, manually controlled means'adapted :whenactuated to render the car-carried I source of light active to infiuencelthe track I wav light sensitive cell,,trackway means,

controlled by the trackway cell effective];

under clear traflic conditions to render the' trackway source of light active to influence the car-carried light sensitive cell, and means controlled by the car-carried cell to release the low speed restriction,

5. Railway trafiic controlling apparatus comprising, a car-carried means arranged to at times establish a restrictive tra'flic condition for the car, a car-carried source: of light and a car-carried light sensitive cell, a-trackway source of light and a trackway light sensitive cell, manually controlled means adapted to render the car-carried source of light active to influence the trackway light sensitive cell, trackivay inc-anscontrolled.by the trackivay cell 'efl'ective under clear trallic conditions to render the trackwaysource of light active to influence the car-carried light sensitive cell, and

means controlled by the car-carried cell to establish a non-restrictive tiaflic condition for the car. i 1

6.' Railway trafiic controlling apparatus comprising, car-carried v car-governing ineans'having different conditions, a carcarried source of light and a car-carried light sensitive element, a trackway source of light and a trackway light sensitive=clement, ineansfor at tinies'renderi-ng the carcarried source of light active to influence the trackway light sensitive element, means controlledjointly by said trackway element and traflic conditions torender the trackway source of light active to influence the car-carried light sensitive element, and means controlled by said car-carried ele-- ment' to establish a given condition of the car-governing means. a

7. Railway tr afiic controlling apparatus comprising, aitrackway light sensitive ele ment, a carcarried' source of light adapted to at times influence said trackway light sensitive element, a car-carried light sensi-' tive element, a trackwaysource of light adapted when active to influence said carcarried light sensitive element," trackway means effective under certain traflic conditionsin, response'to the influencing of the trackway light sensitive element by the carcarried source of light to render the trackway source of light active to influence the car-carrried light sensitive element, and

car-governing means arranged to establish a given operating condition in response to I the influencing of said car-carried element. 8.'The method of conveying asignal in'- dication from 'atrackwayto apassing car which consists'in pro ecting a light beamfrom the car to a trackway'photoelectric device, then projecting a light beam from,

' toelectric device, then projecting a lightbeam from the trackway to afcar-carried photoelectric device in accordance with the influence on said trackway photoelectric device and traffic conditions in advance, and

establishing a speed governing condition for said car in accordance with the in fluence on said car-carried photoelectric device. f e v V a 10. Railway t 'afiie controlling apparatus including, a car-carried relay adapted when dcenergized to establish a restrictive operating condition, a car-carried source of light and a light responsive element, a trackway source of light and a light responsive element, means controlled by {the track- Way light responsive elementunder clear trafli'c conditions to illuminate the trackvvay source of lightin response to a beam of light projected by the car-carried source of light,

and means controlled by the car-carried light responsive element to energize said relay in response toa beam of light projected by the trackway source of light for annulling the restrictive operating condition.

11. Railway traffic controlling apparatus including,a car-carried relay adapted when energized to establish a given operating con. dition, a car-carried SOUIYZB of light adapted vwhen illuminated to at times influence a trackway light sensitive element, a trackway source of light adapted when illuminated to at times influence a car-carried light sensitive element,means governed by said trackway element under clear traffic conditions inresponse to influence by the car-carried source of light to illuminate the trackway source of light for influencing the car-carried light sensitive element, means governed by said. car-carried element in response to said influence by the trackway source of light to energize said .relay to establish the. given operation condition, and 3 means on the car for causing the car-carried source, of light to become illuminated.

12. Railway trafiic controlling'apparatus comprising, trackway means having astopping or a non-stopping condition according as traflic conditions in advance are unsafe or safe, a car-carried car-governing means arranged to be operated by said trackway means when the latter is in its stopping condition but not in its non-stopping condition, a car-carried source of light, a manually controlled means adapted when actuated to illuminate said source of light, and a light sensitive trackway element influenced b light radiated from said source to establish the non-stopping condition of said trackway; means irrespective of trafiic conditions in advance. y

13. Railway trafficv controlling apparatus comprising, trackway' means having a stopping and a non-stopp1ng condition according as tratiic conditions in advance are,

unsafe or safe a car-carried car-governing means arranged to be operated by said trackway means when the. latter is in its stopping condition but not in its non'stopping condition, a car-carried source of light, a manually controlled acknowledging means adapted when actuated to illuminate said source of light and to establish a low speed condition for said car, and a trackway photoelectric cell arranged to be influenced by light from said car source for establishing the non-stopping condition of said trackway means irrespective of trafiic conditions.- 14. Railway traflic controlling apparatus comprising, a track section, a normally energized track relay for thersection, a trackway trip arm located slightly in advance of the entrance of the section for governing trafiic through said section and movable to a non-tripping or a tripping position according as traffic conditions in advance are safe or unsafe, a car-carried brake applying trip arm arranged to be operated by the traclzway trip arm when the latter is in its tripping position but not when it is in its non-tripping position, a car-carried source of light, a trackway photoelectric cell and a normally deenergized relay associated therewith arranged to energize said relay when the photoelectric cell is influenced by light from said car-carried source, a circuit including a front contact of the relay associated with the photoelectric cell and a back contact of said track relay adapted when closed to move the trackway trip arm to its non-tripping position, and manually controlled means on the car to illuminate the source of light and thereby cause the trackway trip arm to be moved to its non-tripping position as the car enters the section. 15. Controlling means for a power driven vehicle arranged to travel along a given traekway comprising, a vehicle-carried source of light, a photocell located along the trackway arranged to be influenced by light from said vehicle-carried source, a trackway source of light controlled in part by the trackway photocell and in part by traflie conditions of said trackway, a vehiclecarried photocell arranged to be influenced by light from the traekway source, a vehicle governing means controlled by said vehiclecarri d photocell, and a vehicle-carried manually controlled means for illuminating the vehicle-carried source of li ht. In testimony whereof I a x my signature.

BERNARD E. OHAGAN. 

